.\" Copyright (c) 2006 John Kasunich
.\"                (jmkasunich AT users DOT sourceforge DOT net)
.\"
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.\" modify it under the terms of the GNU General Public License as
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.TH STREAMER "9"  "2006-11-18" "LinuxCNC Documentation" "HAL User's Manual"
.SH NAME
streamer \- stream file data into HAL in real time
.SH SYNOPSIS
.B loadrt streamer
.BI depth= depth1[,depth2...]
.BI cfg= string1[,string2...]

.SH DESCRIPTION
.B streamer
and
.BR halstreamer (1)
are used together to stream data from a file into the HAL in real time.
.B streamer
is a realtime HAL component that exports HAL pins and creates a FIFO in shared memory.
.B hal_streamer
is a user space program that copies data from stdin into the FIFO, so that
.B streamer
can write it to the HAL pins.

.SH OPTIONS
.TP
.BI depth= depth1[,depth2...]
sets the depth of the user->realtime FIFO that
.B streamer
creates to receive data from
.B halstreamer.
Multiple values of
.I depth
(separated by commas) can be specified if you need more than one FIFO 
(for example if you want to stream data from two different realtime threads).
.TP
.BI cfg= string1[,string2...]
defines the set of HAL pins that
.B streamer
exports and later writes data to.  One 
.I string
must be supplied for each FIFO, separated by commas.
.B streamer
exports one pin for each character in
.I string.
Legal characters are:
.IP "" 7
.B F, f
(float pin)
.IP "" 7
.B B, b
(bit pin)
.IP "" 7
.B S, s
(s32 pin)
.IP "" 7
.B U, u
(u32 pin)

.SH FUNCTIONS
.TP
.BI streamer. N
One function is created per FIFO, numbered from zero.

.SH PINS
.TP
\fBstreamer.\fIN\fB.pin.\fIM\fR output
Data from column
.I M
of the data in FIFO
.I N
appears on this pin.  The pin type depends on the config string.
.TP
\fBstreamer.\fIN\fB.curr-depth\fR s32 output
Current number of samples in the FIFO.  When this reaches zero, new data will no longer be written to the pins.
.TP
\fBstreamer.\fIN\fB.empty\fR bit output
TRUE when the FIFO
.I N
is empty, FALSE when valid data is available.
.TP
\fBstreamer.\fIN\fB.enable\fR bit input
When TRUE, data from FIFO \fIN\fR is written to the HAL pins.
When false, no data is transferred.  Defaults to TRUE.
.TP
\fBstreamer.\fIN\fB.underruns\fR s32 read/write
The number of times that
.B sampler
has tried to write data to the HAL pins but found no fresh data in the FIFO.  It increments whenever
.B empty
is true, and can be reset by the
.B setp
command.

.SH "SEE ALSO"
.BR halstreamer (1)
.BR sampler (9)
.BR halsampler (1)

.SH HISTORY

.SH BUGS
Should an 
.B enable
HAL pin be added, to allow streaming to be turned on and off?

.SH AUTHOR
Original version by John Kasunich, as part of the LinuxCNC
project.  Improvements by several other members of
the LinuxCNC development team.
.SH REPORTING BUGS
Report bugs to jmkasunich AT users DOT sourceforge DOT net
.SH COPYRIGHT
Copyright \(co 2006 John Kasunich.
.br
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
